| DIAM | The length of a straight line passing through the center of a circle and connecting two points on the circumference. |
| DIAMETER | A straight line passing through the centre of a circle (8) |
| AXLE | Rod passing through the middle of a wheel (4) |
| RATIO | Pi is one, between the circumference of a circle and its diameter |
| SYMMETRY | The exact correspondence of parts on either side of a straight line or plane (8) |
| ARC | Opposite of a straight line |
| MAINSTREET | *It often runs through the center of town |
| BISECTS | Runs through the center of |
| AXIS | Principal ___ of a mirror is the line passing through the pole and centre of curvature (4) |
| CHORD | Straight line connecting two points on the curve of a circle (5) |
| CENTRE | Word, derived from the Greek for the sharp tip of a pair of compasses, for the middle of a circle (6) |
| STICKFIGURE | Drawing of a human with the head represented by a circle and the body by straight lines (5,6) |
| CHICANE | Series of bends on a racetrack, used to slow cars at the end of a straight (7) |
| BISECTOR | Line through the middle of a circle |
| BRUE | This West Country river runs through the centre of Wadebridge and on to the outskirts of Ugbrooke (4) |
| MERIDIAN | Imaginary great circle passing through the poles on the Earth's surface; or, the peak or zenith (8) |
| TEES | Pegs supporting golf balls; lines through the centres of the "houses" in curling; or, target hobs in quoits (4) |
| VITRUVIANMAN | The ?, drawing by Leonardo da Vinci of a naked male figure inscribed in a circle and square (9,3) |
| RADIUS | Line from the center of a circle to its perimeter |
| KIPP | A move in gymnastics used as a mount and connecting skill in a bar routine (4) |
